Ridiculous Horizontal Spread

[vinniedelpino]

So I'm at a little bit of a loss here. Normally I'd power through this issue with a bunch of additional load development, but with ammo issues being as they are, I figured I'd ask the experts first.

I got 1k 140gr RDFs from the wife for christmas. Long story short, I sent her a link to some 140 VLD blems from midway. My dad chimed in and told her to skip the blems and get the RDFs instead.

I've read about the RDFs liking at least .030 jump, so I crudely measured the distance to the lands with a slotted case and loaded up my first batch at exactly .030. Due to the new (to me) caliber (6.5prc) and limited powder selection, I'm working with 8133, which seems a little too slow and 7828, which may be a little too fast for my application. I loaded up five rounds at .2 grain increments and results are pretty similar across the board. A tiny bit of vertical spread and about 1.5, sometimes two inches horizontal. I've never seen anything like it before.

So far I've:

1. Removed scope caps (objective is very close to the bore.)
2. Retorqued the action to chassis, rings etc.
3. Checked for any other barrel to chassis contact.

Nothing is loose. Any ideas? I'm tempted to pick the load with the least vertical and play with seating depth, but I want to make sure I'm not overlooking anything else first. I've never had load development start off this poorly.

Thanks for the help!

 

[vinniedelpino]

Tell us more about the rifle and your shooting position. Any chance you have had something ding the crown? Muzzle brake? LOP significantly different than you are used to. Have you been shooting a super light recoiling gun and your fundamentals have gone to shit?
An old guru once told me “vertical is your bullet and horizontal is your table manners”. It’s a simplification, I know but it’s somewhere to start.

It's an Xcaliber MTU blank spun up by crown ridge barrel works with a 6.5prc standard reamer. This is in a barrel nut setup on a bighorn origin in an AI chassis. I've shot it both with a brake and without. For the purposes of load development I've been shooting it off a bench with a bipod on the front and a rear sandbag. I've kind of been pounding it down on the bag in the rear and almost free recoiling the rifle. Not even holding the stock, just touching off the trigger. I see zero movement through the optic though. Maybe this is the problem? It's not how I normally shoot.

My fundamentals are probably shit, but if so they've always been shit. Same day I was shooting an AR frankengun and getting about 3/4" at 100. I think that's about all the wilson combat barrel is capable of though. I'm capable of holding a consistent .5-.6 moa on a calm day.

 

[vinniedelpino]

The same old guru also told me That rifles are like women, some of them like to be held and some of them don’t.

I would bet 100 bucks that your horizontal dispersion will go away if you change the way you’re shooting the gun. My guess is the combination of bipod rear bag and “free recoil” technique is probably the problem.

YOu said it’s not the way you normally shoot and then you said you’re usually capable of .5 to .6 MOA shooting. Even during load development, I would probably shoot the way that you know you’re capable of shooting half MOA. At least then you know anything 1/2 or so is your expected accuracy/precision until your technique improves.

That make sense?

Absolutely. I'll get on my belly, load the bipod and let it rip then report back.

Thanks for the help!

 

[spife7980]

Could also be that youre one of those barrels that just doesnt like rdfs so youll become an rdf hater.

I would find something that looked the best like you said and do a little seating depth work on it too. Usually you I can get most anything to shoot at least alright with a little work.

 

[ShtrRdy]

I have been shooting off the bench using a bipod up front and a squeeze bag in back. A couple things that helped me get to a 1/4 minute grouping. First, place one or two heavy sandbags in front of the bipod legs so you have something to push into. Then make sure your shoulder feels relaxed when you break the shot. You're probably already doing this, but break the shot at the bottom of your breathing cycle.

If the technique suggestions don't make any difference, try a different scope.

Good luck. These things can be frustrating to work out.

-- Todd

 

[bdubb]

Save the headache and don't use RDF's. Then with a consistent shooting projectile, address any form or reloading issues that may remain.

 

[vinniedelpino]

Save the headache and don't use RDF's. Then with a consistent shooting projectile, address any form or reloading issues that may remain.

I'm not expecting crazy performance from the RDFs, but I should at least hit MOA at 100 yards.

With the ammo situation being what it is, I can't afford not to shoot them!

 

[Mr Tibbs]

So I'm at a little bit of a loss here. Normally I'd power through this issue with a bunch of additional load development, but with ammo issues being as they are, I figured I'd ask the experts first.

I got 1k 140gr RDFs from the wife for christmas. Long story short, I sent her a link to some 140 VLD blems from midway. My dad chimed in and told her to skip the blems and get the RDFs instead.

I've read about the RDFs liking at least .030 jump, so I crudely measured the distance to the lands with a slotted case and loaded up my first batch at exactly .030. Due to the new (to me) caliber (6.5prc) and limited powder selection, I'm working with 8133, which seems a little too slow and 7828, which may be a little too fast for my application. I loaded up five rounds at .2 grain increments and results are pretty similar across the board. A tiny bit of vertical spread and about 1.5, sometimes two inches horizontal. I've never seen anything like it before.

So far I've:

1. Removed scope caps (objective is very close to the bore.)
2. Retorqued the action to chassis, rings etc.
3. Checked for any other barrel to chassis contact.

Nothing is loose. Any ideas? I'm tempted to pick the load with the least vertical and play with seating depth, but I want to make sure I'm not overlooking anything else first. I've never had load development start off this poorly.

Thanks for the help!

Horizontal stringing is a COAL issue .

 

[ShtrRdy]

Any update to this problem?

 

[Hudsflywater]

you might try a bigger jump, my experience with RDF's is minimum of .050" jump and go longer from there.